This invention relates to fluid displacement apparatus, and more particularly, to a scroll type fluid compressor.
Scroll type fluid displacement apparatus are well known in the prior art. For example, U.S. Pat. No. 801,182 (Creux) discloses a scroll type fluid displacement apparatus including two scroll members each having a circular end plate and a spiroidal or involute spiral element. These scroll members are maintained angularly and radially offset so that the spiral elements interfit to make a plurality of line contacts between their spiral curved surfaces, thereby to seal off and define at least one pair of fluid pockets. The relative orbital motion of the two scroll members shifts the line contacts along the spiral curved surfaces and, therefore, the fluid pockets change in volume. The volume of the fluid pockets increases or decreases dependent on the direction of the orbital motion. Therefore, scroll type fluid displacement apparatus are applicable to compress, expand or pump fluids.
Scroll type fluid displacement apparatus are particularly well-suited for use as a refrigerant compressor in an automobile air conditioner. Generally, it is desirable that the refrigerant compressor for an automobile air conditioner be compact in size and light in weight, since the compressor is placed in the engine compartment of an automobile. However, the refrigerant compressor is generally coupled to an electromagnetic clutch for transmitting the output of an engine to the drive shaft of the compressor. The weight of the electromagnetic clutch therefore increases the total weight of a compressor unit.